Amazing Facts About Freshwater Fish

I like to read about marine fish. I also enjoying watching shows like Dicovery Channel's The Blue Planet series. That TV series in particular provided an amazing looking into the world of freshwater fish. Each book and show seems to have a few interesting tidbits of trivia that I've collected into this article. I think some of these facts really are amazing.

Male Goldfish have an unusual trick that they use as part of their courtship display: they swim up to a female and then roll over and urinate over her nostrils. As strange as this seems, it allows the female to assess many things, including the male's genetic make-up, thus preventing her from breeding with a relative.

Parental Firemouth Cichlids can also recognize their own fry; remarkably, they will kidnap the fry of others and put these on the edge of their own school of offspring so that they, and not their own young, are in harm's way -- a kind of "cichlid shield."

The age at which fish can be considered old varies from species to species. Fish such as guppies and African Killifish would be lucky to attain 12 months, whereas some of the larger catfish and Cyprinids can continue for two or three decades.

Perhaps the most footloose of fish is the mangrove Killifish (Kryptolebias marmoratus). It makes its home in the smallest of water bodies, ranging from crab burrows to mere root holes in the mud and can move easily between each and every situation with flicks of its body. It can even withstand extended periods of emersion, surviving in damp leaf litter for days on end -- one specimen survived happily for 66 days out of water. Admittedly not a pure freshwater fish, but still...